Signaling system



Mmh 22, 193s.

W. W. CRAMER SIGrIULINGv SYSTEM Filed May 18, 1937 /Nvg/vron W W CRAMERA T TORNE V Patented Mar. 22, 1938 yuNiTED STATES PATENT 'OFFICESIGNALING SYSTEM Application May 18, 1937, Serial'No. 143,248

5 Claims.

This invention relates to signaling systemsand particularly to telegraphsystems arranged for transmitting and receiving polarized signals.

It is an object of the invention to provide a simple, efcient andreliable conference circuit for interconnection of three or moresignaling ,stations in a polar telegraph system.

Y This invention is a telegraph repeater circuit comprising a polarizedreceiving relay and a polarized sending relay for each of a pluralitylof branches, one winding of each of the sending relays being connectedin series in a local circuit, the other winding of each sending relaybeing normally short-circuited by contacts of the associated receivingrelay. Operation `of any receiving relay reverses the current in theseries circuit to operate all of the sending relays eX- cept the oneassociated with the operated receiving relay, operation of .thelast-mentioned sending relay being prevented by current through itsnormally short-circuited winding.

The invention will be further described by considering the conferencecircuit shown inv the drawing which forms a part of this specification.The invention is, however, not limited in -its application tothe specicarrangement shown but is applicable to any polar telegraph system 1nwhich conference circuits or multiline repeaters are provided.

Referring to the drawing:

Fig. 1 shows schematically three telegraph stations I0, 2and 30, threecords I4, 24 and 34 for use in interconnecting stations forcommunication, and a conference circuit C comprising jacks I5l 25 and35, receiving relays I1, -21 and 31, sending relays I8, 28 and 38, and acommon control relay 9; and

Fig. 2 shows a cord circuit CD of a type suitable for use with theconference circuit C.

The kconference circuit C is arranged for interconnecting only threestations but may be arranged for interconnecting more than threestations by providing another jack and set of relays' for eachadditional branch of the circuit. The

' switchboard, at which the conference circuit C is provided, is shownVas a manually operated board, but the manually operated equipment can,of course, be replaced by automatic switching equipment. Each of thedouble-ended cords shown schematically in Fig. l are used forinterconnecting subscribers loops and interoice trunks as Well as forestablishing conference connections. Polarized repeating relays areprovided in each ofthe cords as shown in Fig. 2. The operators positionsmay be equipped with,

teletypewriter equipment for communicating with subscribers and otheroperators, and the subscribersstations may `be similarly equipped forcommunicating with operators and other subscribers. For a more completedescription of such a system reference may be had to the copendingapplication of G. A. Locke'et al. Serial No. 459,684, led June 7, 1930.The line jacks i3, 23 and 33 and conference circuit jacks I5, 25 and 35may be multipled to a plurality of positions. A busy lamp BL isassociated with the rst jack of the conference circuit at each positionto which the conference jacks are multipled.

Assume that an operator has received a request for the interconnectionof stations I, 20

and 30, and that the desired interconnection is provided by plugging oneend of cord I4 into jack I3 and the other end into jack I5,V by pluggingone end of cord 24 into jack 23 and the other end into jack 25 and byplugging one end of cord 34 into jack 33 and the other end into jack 35.The sleeve relays I6, 26 and 36 associated with jacks I5, 25 and 35 arethereby operated; and each of these relays closes a circuit foroperating the common control relay 9. Each of the operated sleeve relaysopens a normally closed short circuit around the lower winding of theassociated sending relay, which short circuit is independent 4of theassociated receiving relay, and substitutes a short circuit which isunder control of the as- I sociated receiving relay. With common relay 9operated, a circuit is closed from negative battery 8 through the rightfront contact of relay 9, normally closed contact of relay 31, and frontcontact of relay 36, normally closed contact of relay ,f

V21 and front contact of relay 26, normally closed contact of relay I1and front contact of relay I5, upper winding of relay I8, upper windingof relay 28 and upper winding of relay 38 to ground through the leftfront Contact of relay 9. The current in this circuit is eiective tohold the armatures of relays I8, 28 and 38 on the marking contact asshown in the drawing. The biasing winding of each of the receivingrelays I1, 21 and -31 is energized in a circuit from negative battery atthe normally closed contact of the'associated sending relay to ground atthe upper front contact of the associated sleeve relay; and the upper-windings of receiving relays I1, 21 and 31 are energized in circuitsfrom negative battery at the normally closed contact of the associatedsending relay, through the tip conductors of the associatedione of jacksI5, 25 and 35, through the winding of one repeating relay and contact ofthe other repeating relay in the associated cord,

to positive battery. The current through the windings of receivingrelays I1, 21 and 31 holds the armatures of these relays on theirmarking contacts as shown in the drawing.

When any one of the interconnected stations starts sending a message,the signals are repeated through the cord to the associated receivingrelay of the conference circuit and operation of any one of thereceiving relays causes the operation of all of the sending relaysexcept the one associated with the operated receiving relay, the signalfrom the sending station being thereby repeated through the other cordsto all other interconnected stations. For instance, assume that thestation IIl' is sending. The signals are repeated through the cord tothe receiving relay I1. A spacing signal moves the armature of relay I1to its spacing contact and a marking signa moves the armature of relayI1 to its marking contact. When the armature of relay I1 moves from itsmarking to its spacing contact, the upper winding of relay I8 isdisconnected from negative battery 8 and connected to positive battery 1thereby causing a reversal of the energization of the upper windings ofrelays I8, 28 and 38. The armatures of sending relays 28 and 38 arethereby moved to their spacing contacts, sending a spacing signal to andthrough cords 24 and 34 to stations 20 and 30. The operation ofreceiving relay I1 opens the short circuit around the lower winding ofsending relay I8 and the resulting energization of this winding opposesthe reversed energization of the upper winding and is effective tomaintain the armature of relay I8 on its marking contact. When relay I1next responds to a marking signal, the energization of the upperwindings of relays I8, 28 and 38 is again reversed and the armatures ofrelays 28 and 38 move to their marking positions thus sending a markingsignal to stations 28 and 3U. The operation of either of receiving relay`21 or 31 when station 28 or 38 is sending a message causes a similarsignal repeating operation. If one or more branches of the conferencecircuit are not used in any given conference connection, the associatedsleeve relay will not be operated and operation of its sending relay is,of course, without effect.

When the plugs are removed from jacks I5, 25 and 35, sleeve relays I5,26 and 3G release.

Patching cords may be used to interconnect the subscribers jacks withthe conference circuit, but in this case the conference circuit ismodied so that positive battery is connected to the marking contact andnegative battery to the spacing contact of each of the sending relays ofthe conference circuit.

What is claimed is:

1. In a telegraph system, subscribers stations, a conference circuit,and means includingl said conference circuit for interconnecting aplurality cf said stations, said conference circuit comprising areceiving relay and a sending relay for each interconnected station, theoperating winding of each of said sending relays being connected in aseries circuit and the holding Winding of each of said sending relaysbeing normally short-circuited by contacts of the associated receivingrelay, the operation of any one of the receiving relays being effectiveto reverse the current in said series circuit and to open said shortcircuit around the holding Winding of the associated sending relay.

2. In a telegraph system, subscribers stations, a conference circuithaving a plurality 0l branches, means for connecting a plurality of saidstations to said conference circuit, a polarized signal receiving relayand a polarized signal sending relay for each of said branches, a seriescircuit for energizing one Winding of each of said sending relays,circuits each including another winding of said sending relays, andcontacts for each of said receiving relays for reversing the current insaid series circuit.

3. In a telegraph system, subscribers stations, a conference circuithaving a plurality of branches, means for connecting a plurality of saidstations to said conference circuit, a polarized signal receiving relayand a polarized signal sending relay for each of said branches, anoperating winding and a biasing winding for each of said sending relays,a series circuit for energizing the operating winding of each of saidsending relays, and contacts for each of said receiving relays forreversing the current in said series crcuit and for opening and closinga short circuit around the biasing winding of the associated sendingrelay.

4. In combination in a telegraph system., a plurality of signalingcircuits, a repeater having a plurality of branches, means forconnecting each branch to a different signaling circuit, a pair ofpolarized sending and receiving relays for each of said branches, meanscomprising contact springs of each of said receiving relays forenergizing one winding of each of said sending re- :m-

lays in series, said contact springs of each of said receiving relaysalso being eiective to shortcircuit the other winding of the associatedsending relay, and means comprising another contact of each receivingrelay for reversing the current in the series connected windings of saidsending relays and for energizing said other Winding of the associatedsending relay.

5. In combination in a telegraph system, a

plurality of pairs of polarized sending and receiving relays, aplurality of signaling circuits, each pair of sending and receivingrelays being connected to receive signals from and send signals to adiiTerent one of said signaling circuits, means comprising contacts ofeach of said receiving relays for energizing one winding of each of saidsending relays in series, said contacts of each of said receiving relaysalso being effective to open and close a short circuit around anotherwinding of the associated sending relay, and other contacts of each ofsaid receiving relays for reversing the current in the series connectedwindings of said sending relays and for energizing said other winding ofthe associated sending relay.

WALTER W. GRANIER.

